<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .a {
            height: 100px;
            border: 1px solid #000;

            /* display: inline-flex; */
            display: flex;

            /* align-items: stretch; */
            /* flex-direction: row-reverse; */
            /* justify-content: flex-end; */
            /* flex-direction: column-reverse; */

            justify-content: space-evenly;
        }

        .a div {
            border: 1px solid #000;
            /* height: 20px; */
        }
    </style>
</head>

<body>

    <!-- 
        弹性布局
            display : flex / inline-flex
            flex-direction:row / column / row-reverse / column-reverse(反向) 主轴方向
            justify-content:flex-start / flex-end / center / space-around / space-between / space-evenly;
            align-items:flex-start / flex-end / center / stretch(默认值)
            flex-wrap:wrap;

        特点：
            1 使用弹性盒，(主轴是x轴的时候)高度继承
            2 
     -->

    <div class="a">
        <div class="a1">1</div>
        <div class="a2">2</div>
        <div class="a1">1</div>
        <div class="a2">2</div>
        <div class="a1">1</div>
        <div class="a2">2</div>
    </div>
</body>

</html>